The present disclosure relates to subject matter contained in Japanese Patent Application No. 11-156031 (filed on Jun. 3, 1999), which is expressly incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a treating instrument used through an instrument passage of an endoscope.
2. Description of the Prior Art
In general, a treating instrument for an endoscope has a flexible sheath removably inserted into an instrument-inserting channel of an endoscope and a treating member provided at the distal end of the flexible sheath to perform a treatment for an affected part or the like in the patient""s body. The treating instrument is used with the distal end portion thereof projected forwardly from the exit of the instrument-inserting channel at the distal end thereof.
The instrument-inserting channel of the endoscope, in which the treating instrument is inserted, is formed from a flexible tube and inserted into the insert part of the endoscope over the entire length of the latter. The insert part has a bendable portion provided at the distal end thereof. The bendable portion is bendable with a small radius of curvature by remote control.
Accordingly, the instrument-inserting channel may be bent with a small radius of curvature at a portion thereof which is located in the bendable portion. This causes an increase in frictional resistance to the insertion or removal of the treating instrument in the bendable portion. The frictional resistance acts directly as a resistance to the operation for inserting or removing the treating instrument.
Therefore, the conventional practice is to weaken the firmness of a portion of the flexible sheath that passes through the bendable portion of the endoscope (i.e. a portion of the flexible sheath that is located in the bendable portion when the treating instrument is aimed at an affected part and a portion extending forward of this portion), thereby reducing the frictional resistance to the flexible sheath when it passes through the bendable portion.
In the case of the above-described arrangement, however, the distal end portion of the flexible sheath projected from the exit of the instrument-inserting channel of the endoscope is not sufficiently firm. Therefore, when the treating instrument is aimed at an affected part and the treating member provided at the distal end of the flexible sheath is pressed against the affected part, the distal end portion of the flexible sheath may bend undesirably. In such a case, it is impossible to press the treating member against the affected part firmly to perform the intended treatment accurately.
An object of the present invention is to provide a treating instrument for an endoscope designed so that it is free from the problem of resistance to the operation for inserting or removing the treating instrument, and when the treating member is pressed against an affected part, the distal end portion of the flexible sheath is unlikely to bend, and thus the treating instrument exhibits superior aiming capability.
Other objects and advantages of the present invention will become apparent from the following detailed description of illustrated embodiments of the invention.
According to the present invention, there is provided a treating instrument for an endoscope which includes a flexible sheath removably inserted into an instrument-inserting channel of the endoscope. A treating member is provided at the distal end of the flexible sheath to perform a treatment for an affected part or the like. The firmness of the flexible sheath in the vicinity of the distal end thereof is varied between a forward end portion extending a distance approximately equal to an extent to which the flexible sheath is projected from the instrument-inserting channel and a rear portion adjacent to the forward end portion so that the forward end portion is firmer than the rear portion.